Histone lysine-specific demethylase 1 induced renal fibrosis via decreasing sirtuin 3 expression and activating TGF-β1/Smad3 pathway in diabetic nephropathy

Objective: Diabetic nephropathy (DN) is the leading cause of end-stage renal disease. Histone lysine-specific demethylase 1 (LSD1) is a flavin-containing amino oxidase that can repress or activate transcription. The aim of this study is to explore the mechanism of LSD1 aggravating DN-induced renal fibrosis. Methods: The STZ-induced DN rat model was established for in vivo study. The rats were divided into four groups: Sham, STZ, STZ+Ad-shNC and Ad-shLSD1. The Hematoxylin-eosin (HE) staining was used to evaluate the renal injury. The Immunofluorescence assay was used to determine the LSD1, Fibronectin and alpha-SMA expression. The related protein expression was detected by western blot. Results: Knockdown of LSD1 alleviated STZ-induced renal injury. Moreover, knockdown of LSD1 decreased the expression of serum biochemical markers, containing urine output (24 h), urinary protein (24 h), serum creatinine, BUN and UACR. Furthermore, we proved that knockdown of LSD1 alleviated renal fibrosis in STZ-induced DN rats. In vitro, knockdown of LSD1 suppressed NRK-49F cells activation and overexpression of LSD1 induced renal fibrosis. In addition, knockdown of LSD1 could deactivate TGF-beta 1/Smad3 pathway and promote sirtuin 3 (SIRT3) expression in vivo and in vitro. The rescue experiments confirmed that LSD1 induced renal fibrosis via decreasing SIRT3 expression and activating TGF-beta 1/Smad3 pathway. Conclusion: LSD1 deficiency leads to alleviate STZ-induced renal injury and overexpression of LSD1 induces renal fibrosis via decreasing SIRT3 expression and activating TGF-beta 1/Smad3 pathway, which provides a reasonable strategy for developing novel drugs targeting LDS1 to block renal fibrosis.